Effect Of Different Cuitivation Measures On Mechanized Harvesting In Rapeseed

This study choose Huaza 62,one of the Rapeseed(Brassica napus L.) as the test material, use mechanical directly seeding in the experiements to study the effects of nitrogen and density,row spacing and harvesting time on yield and quality of mechanical harvesting rapeseed.1.By studying the differences of the same rapeseed under mechanization harvesting we found that, the total yield loss increased with the increased plot yield;and the loss rates increased with increasing N rates. So in the actual production, the planting pattern "low nitrogen and high density" should be used to creat an optimum population with tidy branches, moderate height and high yielding which suitable for mechanized harvesting.2.Based on the effects of plant densities and row spacing arrangements on mechanical harvesting yield in rapeseed,in the actual production,LAI(leaf area index) at bud stage and PAI(pod area index) at pod filling stage significantly increase by increasing plant density and reducing the differences between palnt spancing and row spacing. which could help to control individual growth vigoring of rapeseed, guarantee biomass accumulation, and also could significantly reduce the loss rate of mechanized harvesting.3.According to the test results of different harvest stage on the impact of mechanical harvesting rapeseed, the mechanical harvesting yield on May 14 increased by 21.25% and 9.24% over that on May 5 and May 10, respectively. The total loss of mechanical harvesting firstly decreased and then increased with delayed harvest time, with the highest loss rate(15.80%) and lowest loss rate(7.00%) being observed on May 5 and May 17, respectively.Therefore, in order to obtain high yield and lower loss rates, the optimum mechanized harvest time should be taken into consideration.The mechanized harvest yield loss could be controlled within 8% when operated when the moisture of silique was about 12%; and the mechanized harvest could be lasted for 3~4 days depended on weather condition.4.According to the three experiments in this study, the total yield loss in mechanical harvest was composed of shattering loss(SL), harvest loss by combine header(CHL), and cleaning and threshing loss(CTL), in which CTL accounted for the largest proportion of total yield loss(56.87%–92.90%), followed by CHL(7.80%–31.0%) and shattering(less than 5%). The CTL percentage decreased with harvest date, whereas the CHL percentage was greater in later harvest treatment. And the loss due to the seeds in the field(CHL1) occupies the largest proportion of the yield loss caused by combine header(CHL)(approximately 40% to 80%). Therefore, reducing the loss caused by combine header(CHL), especially the loss in the field(CHL1) was the key toreduce the loss rate of mechanical harvesting.